Integrated circuit packages are presently in wide use in the electronics industry in various types of electronic equipment. Integrated circuit packages can be characterized as a high density device having a very high number of electrical circuits packaged therein in a very small area for performing various electronic functions. The circuits that are arranged in an integrated circuit package are not visible, and all that is visible in an inspection of the devices are the aligned, thin, external leads extending from the opposite sides of the package that allow it to be readily inserted into an integrated circuit socket. It has been determined that a bad integrated circuit package normally fails within about one year of the time of its initial use. The failure of an integrated circuit package in actual use can be very expensive. To eliminate such failures of integrated circuit packages in use, it has become common practice to test the integrated circuits in an oven for a period of time that is equivalent to having an integrated circuit package in actual operation for up to one year or more. This is known as a "burn in" process and is resorted to to eliminate any bad integrated circuit packages before they are actually put into use. While subjecting an integrated circuit package to a burn in test procedure is expensive, it is far less expensive than having a bad integrated circuit device fail in actual use. The burn in testing of the integrated circuit package is performed by the manufacturer of the integrated circuits, as well as numerous test facilities, and others.
The burn in procedure is accomplished by means of a burn in board which is in the form of a printed circuit board having integrated circuit sockets electrically connected to the printed circuit on the board. The integrated circuit sockets allow the integrated circuit packages to be readily inserted or removed, as required. A typical burn in printed circuit board will have 11 or 12 rows of integrated circuit sockets mounted thereon with 9 to 16 sockets per row, or approximately 110 to 165 sockets per burn in board. The sockets mounting the integrated circuit packages are electrically connected to the burn in board to allow the integrated circuits mounted on the board to be electrically operated while the entire board is in a burn in oven. The burn in oven is usually maintained at about 125 degrees Centigrade and the burn in board is kept in the oven 72 or more hours. This allows the integrated circuit package to be tested for the desired equivalent of one year of use in actual operation.
At the present time the removal or extraction of the integrated circuit packages from the burn in board or printed circuit board is accomplished manually. An operator inserts a wedge-like device underneath each integrated circuit package and applies pressure and moves the wedge-like device until the wedge forces the integrated circuit package out of the integrated circuit socket. The manual removal of the packages is accomplished one row at a time. The device is constructed so that the extracted integrated circuit package falls into a holding transport tube attached to the back end of the wedge used by the operator. The wedge forces the integrated circuit packages to be removed from the sockets so that the removal operations are not in a plane that is perfectly perpendicular to the board. In addition, in the use of the wedge-like devices, the operators often rock the wedge back and forth to facilitate the removal operation, and thereby reduce the force required for removal of an integrated circuit package. The wedge removal operations as described hereinabove have been found to cause the leads for the integrated circuit packages to bend, or even cause the integrated circuit package proper to break if excessive forces are employed. In order to detect such damage to integrated circuit packages, the operator must inspect each tube of extracted packages and, if damage is found, the entire tube of devices must be dumped out and then returned individually into the transport tube. The manual removal of the integrated circuit packages is fairly slow and physically tiring resulting in an extraction rate on the order of 1500 devices per man-hour. The subsequent checking and required manual handling of the removed packages brings the man-hour output down to 1,000 or less devices. As a result, it has been determined that the manual extraction of the integrated circuit packages from a burn in board, or similar printed circuit board, results in low productivity having an effective extraction rate on the order of 750 to 1,250 packages per man-hour. Also, since many parts are damaged, additional time is required for repair. Additional disadvantages are that all of the integrated circuit packages must be manually inspected. The broken integrated circuit circuits are a complete loss.
There have been attempts at automatic removal of integrated circuit packages by using a multiplicity of the aforementioned types of manual wedges mounted on a moveable carriage, which is manually moved by an operator. This tends to increase the production rate, but still leaves the problem of bent leads, as described hereinabove.
The present invention provides an improved and relatively inexpensive method and apparatus for automatically removing integrated circuit packages from a burn in board, or similar printed circuit boards, without bending the leads for the extracted integrated circuit packages. The apparatus can be readily operated without the need for any special skills or training and less effort is required by the operator than through the use of prior art devices. The method and apparatus of the present invention extracts the integrated circuit packages from the printed circuit boards perpendicular to the plane of the sockets to eliminate the problem of bent leads or broken parts. An operator utilizing the apparatus of the present invention can remove all the integrated circuit packages from a burn in board in accordance with the concept of the present invention in about 30 seconds, or remove 6,000 to 9,000 integrated circuit packages per man-hour. In addition to the machine extraction of the integrated circuit packages, the method and apparatus of the present invention automatically checks the extracted integrated circuit packages for bent leads and automatically separates the packages having bent leads from the undamaged integrated circuit packages. The undamaged integrated circuit packages are accumulated in a manner that permits ready visible inspection by an operator for damaged integrated circuits prior to removal from the machine. The undamaged integrated circuit packages are readily removed from the extraction apparatus by being insertible into a carrying tube adapted to use with the machine for transport to a point of use or shipment. The damaged integrated circuit devices are rejected into a receptacle for later straightening of the bent leads, or other operations, as the package requires.